Is there a way to control the axis that a force field applies force?
You can constrain the spherical force of a field into a cone or a tube, but these are directional.


To achieve the equatorial emission you require I recommend placing a
force field in the middle to distribute particles.
Then 2 more force fields above and below at the polar regions. They
will repel the vertical emitted particles.




Note that in this demonstration I have turned off the initial Normal emission speed.